This paper presents our study on the effect of fillers on mechanical damping of chIorinated butyl rubber above its glass transition temperature，Tg．In the temperature range of TgT>一36℃ the effect of interaction between rubber and fillers on mechanical damping of chlori-nated butyl rubber was studied and discussed in terms of several parameters such as the content of combined rubber absorbed On the surface of fillers，surface area of fillers，the interfacial function ψ，and the surface area of fillers occupied by rubber of unit weight．The effect of interfiller friction on mechanical damping of the filled ruber was described with the parameters ψ and φ．φ is the volume fraction of fillers．It is shown by the results that when the content of the fillers is low．the mechanical damping of filled rubber depends on the interaction between the fillers and rubber．On the other hand，the mechanical damping of the filled rubber was improved no-tably by the friction between the filler particles．